<template>
  <div>
    <table
      border="1"
      width="700"
      style="border-collapse: collapse; margin: 0 auto;"
    >
      <caption>
        购物车
      </caption>
      <thead>
        <tr>
          <th>
            <input type="checkbox" v-model='isAll' @click='clickFn'/> <span>全选</span>
          </th>
          <th>名称</th>
          <th>价格</th>
          <th>数量</th>
          <th>总价</th>
          <th>操作</th>
        </tr>
      </thead>
      <tbody>
        <tr v-for='(item,index) in goodList' :key="index">
          <td>
            <input type="checkbox" v-model="item.checked"/>
          </td>
          <td>{{item.name}}</td>
          <td>{{item.price}}</td>
          <td>
            <button @click='item.num>0 && item.num--'>-</button>
            {{item.num}}
            <button @click='item.num++'>+</button>
          </td>
          <td>{{item.price * item.num}}</td>
          <td>
            <button>删除</button>
          </td>
        </tr>
      </tbody>
      <tfoot>
        <tr>
          <td>合计:</td>
          <td colspan="5">
            {{ sum || 0}}
          </td>
        </tr>
      </tfoot>
    </table>
  </div>
</template>

<script>
export default {
  data() {
    return {
      goodList: [
        {
          name: "诸葛亮",
          price: 1000,
          num: 1,
          checked: false,
        },
        {
          name: "蔡文姬",
          price: 1500,
          num: 1,
          checked: false,
        },
        {
          name: "妲己",
          price: 2000,
          num: 1,
          checked: false,
        },
        {
          name: "鲁班",
          price: 2200,
          num: 1,
          checked: false,
        },
      ],
    };
  },
  methods: {
    clickFn() {
      this.goodList.forEach(i=>i.checked = !i.checked)
    },
  },
  
  computed: {
    sum() {
      return this.goodList.reduce((p,i)=> p + (i.price * i.num), 0)
    },
    isAll: {
      get() {
        return this.goodList.every(i=> i.checked)
      },
      set(val) {
        this.goodList.forEach(i=> i.checked = val)
      }
    }
  }
};
</script>

<style>
</style>